low TCP throughput with 80MHz channel width

[Iñaki Pascual]

We are using kernel 4.2 with CandelaTech firmware 
10.1.467-ct-com-full-014-96d543

monet at sc227:~$ ethtool -i wlan2
driver: ath10k_pci
version: 4.2.0+
firmware-version: 10.1.467-ct-com-full-014-96d543
bus-info: 0000:0b:00.0
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: no
supports-priv-flags: no

Thanks,

Iñaki

On 22/04/16 18:06, Ben Greear wrote:
> On 04/22/2016 09:02 AM, Iñaki Pascual wrote:
>
>> Thanks for the tip Ben. We have moved to 'reno' and tried several 
>> window sizes but we are still on max. 35 Mbps which is too low.
>>
>
> What firmware and kernel are you using?
>
> Thanks,
> Ben
>
>> Bests,
>>
>> Iñaki
>>
>> On 22/04/16 17:40, Ben Greear wrote:
>>> Use 'reno' instead of cubic TCP congestion control, cubic is broken 
>>> with ath10k.
>>>
>>> Thanks,
>>> Ben
>>>
>>> On 04/22/2016 08:32 AM, Iñaki Pascual wrote:
>>>> Hi everyone,
>>>>
>>>> we have configured two boxes with 802.11ac NICs to work in channel 
>>>> 48 (5240 MHz), ad-hoc mode, 80MHz channel width.
>>>> For UDP traffic we get 300 Mbps bandwith but for TCP we are around 
>>>> 30 Mbps.
>>>>
>>>> We have tried other channels with similar results.
>>>> Throughput for 20 and 40 MHz channel width are ok (20MHz: TCP 
>>>> 21Mbps, UDP 27Mbps, 40MHz: TCP 82Mbps, UDP 144Mbps).
>>>>
>>>> Testing with iperf we have also tried different congestion windows 
>>>> with no or low improvements.
>>>>
>>>> Below are config details and the sequence of commands we are using 
>>>> to configure the interface.
>>>>
>>>> Any ideas on what we may be doing wrong?
>>>>
>>>> Bests,
>>>>
>>>> Iñaki
>>>>
>>>> iw outputs:
>>>>
>>>> root at sc227:/home/monet# iw wlan2 info
>>>> Interface wlan2
>>>>      ifindex 6
>>>>      wdev 0x200000001
>>>>      addr 04:f0:21:18:26:a2
>>>>      ssid SC226SC227
>>>>      type IBSS
>>>>      wiphy 2
>>>>      channel 48 (5240 MHz), width: 80 MHz, center1: 5210 MHz
>>>>
>>>> root at sc227:/home/monet# iw wlan2 station dump
>>>> Station 04:f0:21:18:26:a8 (on wlan2)
>>>>      inactive time:    86 ms
>>>>      rx bytes:    467732521
>>>>      rx packets:    364249
>>>>      tx bytes:    1394558
>>>>      tx packets:    16200
>>>>      tx retries:    0
>>>>      tx failed:    0
>>>>      signal:      -51 dBm
>>>>      signal avg:    -51 dBm
>>>>      tx bitrate:    351.0 MBit/s VHT-MCS 4 80MHz VHT-NSS 2
>>>>      rx bitrate:    526.5 MBit/s VHT-MCS 4 80MHz VHT-NSS 3
>>>>      authorized:    yes
>>>>      authenticated:    yes
>>>>      preamble:    long
>>>>      WMM/WME:    yes
>>>>      MFP:        no
>>>>      TDLS peer:    no
>>>>      connected time:    3169 seconds
>>>>
>>>>
>>>> config commands:
>>>>
>>>> ifconfig wlan2 down
>>>> iw wlan2 set type ibss
>>>> ifconfig wlan2 up
>>>> ifconfig wlan2 10.2.1.7 netmask 255.255.255.0
>>>> iw wlan2 ibss join SC226SC227 5240 80MHz
>>>>
>>>> iperf:
>>>> root at sc227:/home/monet# iperf -c 10.2.1.6
>>>> ------------------------------------------------------------
>>>> Client connecting to 10.2.1.6, TCP port 5001
>>>> TCP window size: 85.0 KByte (default)
>>>> ------------------------------------------------------------
>>>> [  3] local 10.2.1.7 port 48548 connected with 10.2.1.6 port 5001
>>>> [ ID] Interval       Transfer     Bandwidth
>>>> [  3]  0.0-10.0 sec  33.1 MBytes  27.7 Mbits/sec
>>>>
>>>> _______________________________________________
>>>> ath10k mailing list
>>>> ath10k at lists.infradead.org
>>>> http://lists.infradead.org/mailman/listinfo/ath10k
>>>
>>>
>>
>
>